现代心脏病学Word文档格式.docx

1、 Cheryl L. Reid, MDGeneral ConsiderationsPhysiology & EtiologyClinical FindingsTreatmentPrognosisESSENTIALS OF DIAGNOSISPregnancyHistory of heart diseaseSymptoms and signs of heart diseaseEchocardiographic evidence of heart diseaseHeart disease （most frequently congenital or valvular diseases） occur

2、s in 14% of pregnancies, and the incidence is increasing. The unique hemodynamic changes associated with pregnancy make diagnosis and management of heart disease in pregnant patients a challenge to the physicians, who must consider not only the patient but also the risks to the fetus.Danzell JD: Pre

3、gnancy and pre-existing heart disease. J La State Med Soc 1998;150（2）:97.A. CARDIOVASCULAR PHYSIOLOGY OF “NORMAL” PREGNANCYNormal pregnancy is accompanied by significant physiologic changes, although underlying mechanisms remain virtually unknown （Table 311）. The normal signs and symptoms associated

4、 with pregnancy may obscure the diagnosis of heart disease during that time. The clinician must, therefore, have a thorough knowledge of these normal changes and the aspects of the history and physical examination that suggest the presence of heart disease. Table 311. Cardiovascular changes in norma

5、l pregnancy.1. Blood volumeThe increase in maternal blood volume begins as early as the sixth week of pregnancy, peaks at approximately 32 weeks of gestation, and stays at that level （4050% higher than pregestational levels） until delivery. The plasma volume shows a more rapid and significant rise t

6、han the red blood cell mass, accounting for the appearance of physiologic anemia during pregnancy. The increased blood volume is maintained until after delivery, when a spontaneous diuresis occurs. This rapid postpartum change in blood volume is a critical period for patients with underlying heart d

7、isease.2. Cardiac functionNormal pregnancy is characterized by enhanced myocardial performance. Numerous studies have shown a gradual increase in left ventricular systolic function attributed to left ventricular afterload reduction due to the low-resistance runoff of the placenta. Then rise in left

8、ventricular systolic function begins in early pregnancy, peaks in the twentieth week, and then remains constant until delivery.3. Cardiac outputOne of the most significant changes during pregnancy is the increase in cardiac output, which begins to rise during the first trimester and peaks at twenty-

9、fifth and thirty-fifth weeks of gestation. Total cardiac output increases up to 50% over pregestational levels. Cardiac output is the product of stroke volume and heart rate. During the early part of pregnancy, the increase in cardiac output is predominantly the result of an increase in stroke volum

10、e, augmented by increased intrinsic myocardial contractility. As pregnancy advances, heart rate increases and stroke volume mildly decreases. The increased cardiac output in late pregnancy is maintained because of the increased heart rate.A unique aspect of pregnancy is the hemodynamic changes induc

11、ed by a change in a patients position. When the patient is in the supine position, the gravid uterus induces profound mechanical compression of the inferior vena cava, decreasing venous return to the heart, and thus, cardiac output. A change from the supine to the left lateral position results in a

12、2530% increase in cardiac output because of an increase in stroke volume.4. Intravascular pressures and vascular resistanceSystolic and diastolic pressures drop during pregnancy. A small decrease in systolic blood pressure begins in the first trimester, peaks at midgestation, and returns to near pre

13、pregnancy levels at term. The diastolic blood pressure decreases more than the systolic blood pressure, due to a significant fall in systemic vascular resistance, and results in a wider pulse pressure. The systemic blood pressure increases during pregnancy with the patients age and parity. It also v

14、aries with the patients position. The highest levels are recorded early in the pregnancy when the patient is upright, and lowest when she is supine. During the latter part of pregnancy the effect of position on systemic blood pressure depends on the relative degrees of inferior vena cava and aortic

15、compression. Total vascular resistance, including both the systemic and the pulmonary, decrease during pregnancy. The mechanism for the fall in resistances is poorly understood but is attributed to the low-resistance circulation of the pregnant uterus and to hormonal changes associated with pregnanc

16、y.Thornburg KL, Jacobson SL, Giraud GD et al: Hemodynamic changes in pregnancy. Semin Perinatol 2000;24（1）:11.Gilson GJ, Samaan S, Crawford MH et al: Changes in Hemodynamics, ventricular remodeling, and ventricular contractility during normal pregnancy: A longitudinal study. Obstet Gynecol 1997;89（6

17、）:957.Poppas A, Shroff SG, Korcarz CE et al: Serial assessment of the cardiovascular system in normal pregnancy. Role of arterial compliance and pulsatile arterial load. Circulation 1997;20; 95（10）:2407.B. ETIOLOGY AND SYMPTOMATOLOGY1. Congenital heart diseaseAs medical and surgical treatment of suc

18、h patients has improved, congenital heart disease is found more frequently during pregnancy. As a result, more women with either uncorrected or surgically corrected congenital heart diseases are surviving into the adulthood （Table 312）. Table 312. Common congenital abnormalities found in pregnant wo

19、men.Only a few conditions place a patient at a high risk to advise against pregnancy （Table 313）. A majority of the patients with mild to moderate acyanotic congenital heart disease tolerate pregnancy, labor, and delivery well. Treatment should involve frequent counseling by the obstetrician and car

20、diologist. In severe cases, physical activity and salt intake limitation, early treatment of any infection, heart failure, and arrhythmia should be undertaken. Cesarean delivery should be reserved only for obstetric indications because most patients can be safely delivered vaginally.Table 313. Relat

21、ive contraindications to pregnancy.High-risk patients with severe cyanotic congenital heart disease, decreased functional capacity, or Eisenmengers syndrome should be advised against pregnancy. Antibiotic prophylaxis for bacterial endocarditis is recommended in most patients with congenital heart di

22、sease. The risk of fetal malformation in the offspring should be considered carefully.a. Atrial septal defectSecundum atrial septal defect is the most common congenital cardiac abnormality encountered during pregnancy. Patients with uncomplicated atrial septal defects usually tolerate pregnancy with

23、 little problem. Patients may not be able to tolerate the acute blood loss that can occur at the time of delivery because of increased shunting from left to right caused by systemic vasoconstriction associated with hypotension. The incidence of supraventricular arrhythmias may increase in older preg

24、nant patients, which may result in right ventricular failure and venous stasis leading to paradoxical emboli. Low-dose aspirin, once daily after the first trimester until delivery may help prevent clot formation. Pulmonary hypertension from an atrial septal defect usually occurs late in life, past t

25、he childbearing years. Bacterial endocarditis prophylaxis is recommended only for ostium primum defect due to associated aortic valve abnormality. Vaginal delivery is preferred over cesarean. Risk in the offspring is about 2.5%.b. Ventricular septal defectMost isolated ventricular septal defects hav

26、e closed by adulthood. Women with ventricular septal defects generally fare well in pregnancy. Congestive heart failure and arrhythmia are reported only in patients with decreased left ventricular systolic function prior to pregnancy. Endocarditis prophylaxis during delivery, preferably vaginal, is

27、recommended.c. Patent ductus arteriosusMost patients with a patent ductus arteriosus undergo surgical repair in childhood. A normal pregnancy can be expected in patients with small-to-moderate shunts and no evidence of pulmonary hypertension. Patients with a large patent ductus arteriosus, elevated

28、pulmonary vascular resistance, and a reversed shunt are at greatest risk for complications during pregnancy. The decreased systemic vascular resistance associated with pregnancy increases the right-to-left shunt and the intrauterine oxygen desaturation. Patients developing heart failure are treated

29、with digoxin and diuretics. The preferred mode of delivery is vaginal in most patients with endocarditis prophylaxis and hemodynamic monitoring considered at the time of delivery. The risk in an offspring is about 4%.d. Pulmonic stenosisThe natural history of pulmonic stenosis favors survival into a

30、dulthood even with severe obstruction to right ventricular outflow. Mild-to-moderate pulmonic stenosis （peak gradient 100 mm Hg） usually presents no increased risk during pregnancy. Patients with severe pulmonic stenosis may occasionally tolerate pregnancy without developing congestive heart failure

31、. Vaginal delivery is tolerated well. Ideal treatment consisting of balloon valvuloplasty should be performed before gestation. The risk in the offspring is about 3.5%.e. Coarctation of the aortaIn uncomplicated coarctation of the aorta, pregnancy is usually safe for the mother but may be associated

32、 with fetal underdevelopment because of the diminished uterine blood flow. The blood pressure may decrease slightly, as during normal pregnancy, but still remains elevated. Maternal deaths in these patients are usually the result of aortic rupture or cerebral hemorrhage from an associated berry aneurysm of the circle of Willis. Patients with the greatest risk during pregnancy are those with severe hypertension or associated cardiac abnormalities, such a